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<h2>stnmap</h2>
<code>stnmap [ -<i>i fname</i> ]</code><p>
<h3>Usage Notes</h3>
<code>stnmap</code> is a GrADS utility  that  writes  out  a  hash
table
     and/or  link  list  information for station data that allows
     GrADS to access the report data more efficiently.
     <p>
If you change the data file - perhaps by  appending  another
     time  group  -  you  will also have to change the descriptor
     file to reflect the changes - the new number  of  times  for
     example - and then rerun the <code>stnmap</code> utility.
     <p>
Note the difference between station descriptor  file  and  a
     grid descriptor file:<p>
<ul>

<code>DTYPE</code>&nbsp;&nbsp;&nbsp;&nbsp;               specify a data
type of: station<p>
<code>STNMAP</code>&nbsp;&nbsp;&nbsp;&nbsp;              gives the file
name of the station mapping file.     <p>
<code>XDEF, YDEF, ZDEF</code>&nbsp;&nbsp;&nbsp;&nbsp;    not
specified.<p>
<code>TDEF</code>&nbsp;&nbsp;&nbsp;&nbsp;                describes the
time grouping interval and
                         the  number  of  the  time groups in the
                         file.<p>

<code>VAR</code>&nbsp;&nbsp;&nbsp;&nbsp;                 surface
variables must come first, and
                         are     given    a    zero    for    the
                         number-of-levels field. Level  dependent
                         variables  are  listed after the surface
                         variables,  and are given a one  in  the
                         number-of-levels field.</ul><p>
<h3>Examples</h3>
When a data set, for example <code>ua.reps</code>  is  written,  and
the
     descriptor  file <code>stat.ctl</code>, including the information
records
     for the station data file <code>ua.reps</code>  is  created,  you
should
     then create the station map file <code>ua.map</code> (named in the
<code>STNMAP</code>
     record of the descriptor file; see  below)  by  running  the
     <code>stnmap</code> utility.<p>
Example descriptor file: <code>stat.ctl</code>
<ul>
<code>
 DSET   ^ua.reps<br>
                    DTYPE   station<br>
                    STNMAP ^ua.map<br>
                    UNDEF   -999.0<br>
                    TITLE   Real Time Upper air obs<br>
                    TDEF    10 linear 12z18jan1992 12hr<br>
                    VARS    12<br>
                      &nbsp;&nbsp;slp   0  99  SLP<br>
                      &nbsp;&nbsp;ts    0  99 Temps<br>
                      &nbsp;&nbsp;us    0  99  U Winds<br>
                      &nbsp;&nbsp;vs    0  99  V Winds<br>
                      &nbsp;&nbsp;z     1  99  Heightsa<br>
                      &nbsp;&nbsp;t     1  99  Temps<br>
                      &nbsp;&nbsp;u     1  99  U Winds<br>
                      &nbsp;&nbsp;v     1  99  V WInds<br>
                    ENDVARS</code></ul><p>
Running the <code>stnmap</code> utility:<p>
<dd>                    <code>stnmap -i stat.ctl</code><p>
     The station map file <code>ua.map</code> is a binary file, which
includes
     the hash table and/or link list information.
